A vessel sterilization apparatus, which sterilizes a vessel conveyed in a state of being held by a gripper of a vessel conveying device by irradiating the vessel with electron beam from an electron beam irradiator, is conventionally known (for example, refer to Patent Document 1). The electron beam irradiator described in this Patent Document 1 is provided with a plurality of vessel holding means (grippers) around a rotary body at an equal interval in a circumferential direction, and the vessels are held by such vessel holding means, respectively, and are rotated and conveyed by the rotation of the rotary body. The electron beam irradiator is arranged along a conveying path so as to irradiate the vessel with the electron beam during the conveyance thereof in the state of being held by the vessel holding means.    Patent Document 1: Japanese Patent Application Laid-open Publication No. 2007-29709